1. Field
Embodiments of the invention relate generally to a solid-state imaging device and a method for manufacturing the same.
2. Background Art
Solid-state imaging devices have recently been finding widespread application not only in digital cameras, but also in cell phones and various other mobile terminals, surveillance cameras, and web cameras for chatting through the Internet.
Such solid-state imaging devices are required to achieve low power consumption and small size. As a solid-state imaging device satisfying these requirements, a CMOS (complementary metal oxide semiconductor) area sensor (hereinafter referred to as CMOS sensor), a CCD (charge-coupled device) area sensor, or the like is drawing attention.
In an example of the CMOS sensor, a light receiving section made of a photodiode or the like is formed in the surface portion of a silicon substrate, and a multilayer wiring layer is formed on the silicon substrate outside the light receiving section. Furthermore, a trench is formed immediately above the light receiving section, and an optical waveguide for guiding light to the light receiving section is placed inside this trench (see, e.g., JP-A 2007-317859 (Kokai)).
In this type of solid-state imaging device, a microlens for focusing light and a color filter for transmitting light only in a particular wavelength range are provided above the optical waveguide. On the other hand, the pitch reduction (miniaturization) of solid-state imaging devices is advancing rapidly to achieve higher resolution. Accordingly, the width of the optical waveguide is also narrowed.
However, with the narrowing of the optical waveguide width, filling failure of the optical waveguide material occurs, causing a problem of decreasing the light receiving efficiency of the solid-state imaging device.